The present invention relates to computer animation. More particularly, the present invention relates to techniques and apparatus for memory and time efficiency in processing complex scenes.
Throughout the years, movie makers have often tried to tell stories involving make-believe creatures, far away places, and fantastic things. To do so, they have often relied on animation techniques to bring the make-believe to “life.” Two of the major paths in animation have traditionally included, drawing-based animation techniques and stop motion animation techniques.
Drawing-based animation techniques were refined in the twentieth century, by movie makers such as Walt Disney and used in movies such as “Snow White and the Seven Dwarves” and “Fantasia” (1940). This animation technique typically required artists to hand-draw (or paint) animated images onto a transparent media or cels. After painting, each cel would then be captured or recorded onto film as one or more frames in a movie.
Stop motion-based animation techniques typically required the construction of miniature sets, props, and characters. The filmmakers would construct the sets, add props, and position the miniature characters in a pose. After the animator was happy with how everything was arranged, one or more frames of film would be taken of that specific arrangement. Stop motion animation techniques were developed by movie makers such as Willis O'Brien for movies such as “King Kong” (1932). Subsequently, these techniques were refined by animators such as Ray Harryhausen for movies including “The Mighty Joe Young” (1948) and Clash Of The Titans (1981).
With the wide-spread availability of computers in the later part of the twentieth century, animators began to rely upon computers to assist in the animation process. This included using computers to facilitate drawing-based animation, for example, by painting images, by generating in-between images (“tweening”), and the like. This also included using computers to augment stop motion animation techniques. For example, physical models could be represented by virtual models in computer memory, and manipulated.
One of the pioneering companies in the computer aided animation (CAA) industry was Pixar. Pixar developed both computing platforms specially designed for CAA, and animation software now known as RenderMan®. RenderMan®was particularly well received in the animation industry and recognized with two Academy Awards®. One of these awards recognized the inventor of the present patent application, and others, with a Scientific And Engineering Achievement Award® in 1992.
RenderMan® software is used to convert graphical specifications of objects and convert them into one or more images. This technique is known in the industry as rendering. One specific portion of the rendering process is the graphical specification of objects to be rendered. Objects may refer to geometric objects in the image, lighting objects, camera objects, and the like. In this process, objects may be pre-defined and pre-specified, objects may be defined procedural techniques, objects may be defined by a combination of these techniques, or the like.
Typically scenes to be rendered are specified (assembled) by one or more animators. These scenes include descriptions of the objects, camera angles, lighting sources, and the like. Once a scene is defined, the scene data stored and/or the scene is rendered. The resulting image is then viewed by the animators. If the animators do not like the appearance of the rendered image, the animators re-specify the scene data and the process repeats.
Drawbacks with the above techniques include that there are a great number of objects in a typical scene, each typically having a great number of parameters that can or must be set by the animator. The scene data file (also known as a scene descriptor file) that describes the entire scene is accordingly, typically very large (gigabytes). Because of the sizes of typical scene descriptor files are typically large, the animator's computer must have sufficient amount of memory. As an another drawback, because scene descriptor files are typically large, the animators typically have to wait for the descriptor files to be retried from memory. Additionally, because scene descriptor files are typically large, the animators typically have to wait a long time for the scene to be rendered.
In light of the above, what is needed are improved techniques for animators to specify scenes without the drawbacks described above.